They will take what cost reduction schemes they can until R&D can catch up, but by then SpaceX will be flying theor next generation methane fueled launchers, the next-gen Dragon and deep space MCT spacecraft.

Using methane gives very close to liquid hydrogen performance without the need for the very expensive cryogenic hardware, and it doesn't have the boil-off problems that make fuel depots and long missions tough. This leaves toxic hypergolic fuels like the hydrazine famuly, which work but are inefficient and very hard to handle.

Using methane gives very close to liquid hydrogen performance without the need for the very expensive cryogenic hardware, and it doesn't have the boil-off problems that make fuel depots and long missions tough. This leaves toxic hypergolic fuels like the hydrazine famuly, which work but are inefficient and very hard to handle.

completely incorrect:

Methane has a boiling point of −161 °C (−257.8 °F) at a pressure of one atmosphere.

+ oxidizer out there is LOX, so there'll be gotten Just yet another cryogenic rocket. actually, only niche i can see is to use Methane for low-power upper stages. seems it has good odds to beat Hydrogen: LH2 is worst choice to gain powerful thrust because of problems to cool engines.

Hydrogen is the clear Isp winner, with methane second. Both will deliver much more "mpg" than NTO4+MMH, which are also highly toxic - complicating ground operations, but with hydrogen there are storage issues.

First, liquid hydrogen is cryogenic so that takes expensive hardware and storage or it'll boil off easily. Second, it is a very tiny molecule that will infiltrate most materials it touches, degrading them over time. As a result special materials or coatings are required.

Bottom line: liquid hydrogen hardware dramatically ups costs.

Methane gives "good enough" Isp, much higher than hypergolics, and does not have near the storage issues of hydrogen.

The hypergolics low Isp is a problem, but toxicity alone is why most companies and nations are actively developing replacements for them. They greatly complicate ground opetations, and crashed hypergolic stages have killed civilians (China, mitric acid+hydrazine).

These advantages over hypergolics and hydrogen are enough that, in addition to SpaceX, Russia is now developing the RD-0162/0164 methane engines for the future Soyuz 5 launcher.

My understanding with methane propellent is that since the density is higher than hydrogen, it would require less storage volume in a fuel tank. A storage tank with less volume would mean a rocket with less mass.

My understanding with methane propellent is that since the density is higher than hydrogen, it would require less storage volume in a fuel tank. A storage tank with less volume would mean a rocket with less mass.

That's known as bulk density and yes, methane is better than liquid hydrogen.

Methane: 801 kg/m^3
Hydrogen: 358 kg/m^3

and for SarK0Y's sake

MMH: 972 kg/m^3, but for long missions or fuel depots it'll freeze solid as a rock without heavy extra insulation heaters in the tank. Not to mention its highly toxic.

My understanding with methane propellent is that since the density is higher than hydrogen, it would require less storage volume in a fuel tank. A storage tank with less volume would mean a rocket with less mass.

it'd be heavier than Hydrogen, but Methane looks better in terms of thrust because there needs less volume to cool engines. In short, at greater thrust, we could hope upon mass savings too.

DocM, it's truly fascinating comment from you how long do you Hope to store Methane in the spacecraft at stable state?

A lot longer than you can hydrogen, which requires active cooling and heavier insulation to prevent boil-off, then there is th problem of hydrogen infiltration damage which requires many expensive materials that methane doesn't need.

this comparison has no ground because Hydrogen never has been used for long-lasting missions. if you want to store Methane for days/weeks/months/.., you need active cooling. where'd you mind to take energy for, DocM???